Shared memory packet interface (memif) library

Change-Id: I5097462ae85acd705f19e92517c01094dba7565f
Signed-off-by: Jakub Grajciar <grajciar.jakub@gmail.com>

1 files changed, 921 insertions, 0 deletions

diff --git a/extras/libmemif/examples/icmp_responder-mt/main.c b/extras/libmemif/examples/icmp_responder-mt/main.c
new file mode 100644
index 00000000000..860569bc20b
--- /dev/null
+++ b/extras/libmemif/examples/icmp_responder-mt/main.c
@@ -0,0 +1,921 @@
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <net/if.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/uio.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <inttypes.h>
+#include <string.h>
+#include <stdio.h>
+#include <netdb.h>
+#include <linux/ip.h>
+#include <linux/icmp.h>
+#include <arpa/inet.h>
+#include <stdlib.h>
+#include <netinet/if_ether.h>
+#include <net/if_arp.h>
+#include <asm/byteorder.h>
+#include <byteswap.h>
+#include <string.h>
+#include <sys/epoll.h>
+#include <errno.h>
+#include <unistd.h>
+#include <signal.h>
+#include <pthread.h>
+
+#include <libmemif.h>
+#include <icmp_proto.h>
+
+#define APP_NAME "ICMP_Responder"
+#define IF_NAME  "memif_connection"
+
+
+#ifdef ICMP_DBG
+#define DBG(...) do {                                               \
+                    printf (APP_NAME":%s:%d: ", __func__, __LINE__);         \
+                    printf (__VA_ARGS__);                           \
+                    printf ("\n");                                  \
+                } while (0)
+#else
+#define DBG(...)
+#endif
+
+#define INFO(...) do {                                              \
+                    printf ("INFO: "__VA_ARGS__);                   \
+                    printf ("\n");                                  \
+                } while (0)
+
+/* maximum tx/rx memif buffers */
+#define MAX_MEMIF_BUFS  256
+#define MAX_CONNS       50
+#define MAX_QUEUES      2
+#define MAX_THREADS     ((MAX_CONNS) * (MAX_QUEUES))
+
+int main_epfd;
+
+typedef struct
+{
+  /* thread id */
+  uint8_t id;
+  /* memif connection index */
+  uint16_t index;
+  /* id of queue to be handled by thread */
+  uint8_t qid;
+  uint8_t isRunning;
+
+  uint16_t rx_buf_num;
+  uint16_t tx_buf_num;
+  memif_buffer_t *rx_bufs;
+  memif_buffer_t *tx_bufs;
+} memif_thread_data_t;
+
+typedef struct
+{
+  uint16_t index;
+  /* memif conenction handle */
+  memif_conn_handle_t conn;
+  /* interface ip address */
+  uint8_t ip_addr[4];
+  /* inform pthread about connection termination */
+  uint8_t pending_del;
+} memif_connection_t;
+
+memif_connection_t memif_connection[MAX_CONNS];
+long ctx[MAX_CONNS];
+
+/* thread data specific for each thread */
+memif_thread_data_t thread_data[MAX_THREADS];
+pthread_t thread[MAX_THREADS];
+
+void
+user_signal_handler (int sig)
+{
+  sig = sig;
+}
+
+static void
+print_memif_details ()
+{
+  memif_details_t md;
+  ssize_t buflen;
+  char *buf;
+  int err, i, e, ti;
+  buflen = 2048;
+  buf = malloc (buflen);
+  printf ("MEMIF DETAILS\n");
+  printf ("==============================\n");
+  for (i = 0; i < MAX_CONNS; i++)
+    {
+      memif_connection_t *c = &memif_connection[i];
+
+      memset (&md, 0, sizeof (md));
+      memset (buf, 0, buflen);
+
+      err = memif_get_details (c->conn, &md, buf, buflen);
+      if (err != MEMIF_ERR_SUCCESS)
+	{
+	  if (err != MEMIF_ERR_NOCONN)
+	    INFO ("%s", memif_strerror (err));
+	  continue;
+	}
+
+      printf ("interface index: %d\n", i);
+
+      printf ("\tinterface ip: %u.%u.%u.%u\n",
+	      c->ip_addr[0], c->ip_addr[1], c->ip_addr[2], c->ip_addr[3]);
+      printf ("\tinterface name: %s\n", (char *) md.if_name);
+      printf ("\tapp name: %s\n", (char *) md.inst_name);
+      printf ("\tremote interface name: %s\n", (char *) md.remote_if_name);
+      printf ("\tremote app name: %s\n", (char *) md.remote_inst_name);
+      printf ("\tid: %u\n", md.id);
+      printf ("\tsecret: %s\n", (char *) md.secret);
+      printf ("\trole: ");
+      if (md.role)
+	printf ("slave\n");
+      else
+	printf ("master\n");
+      printf ("\tmode: ");
+      switch (md.mode)
+	{
+	case 0:
+	  printf ("ethernet\n");
+	  break;
+	case 1:
+	  printf ("ip\n");
+	  break;
+	case 2:
+	  printf ("punt/inject\n");
+	  break;
+	default:
+	  printf ("unknown\n");
+	  break;
+	}
+      printf ("\tsocket filename: %s\n", (char *) md.socket_filename);
+      printf ("\trx queues:\n");
+      for (e = 0; e < md.rx_queues_num; e++)
+	{
+	  ti = (i * MAX_QUEUES) + e;
+	  printf ("\tqueue id: %u\n", md.rx_queues[e].qid);
+	  printf ("\t\tring size: %u\n", md.rx_queues[e].ring_size);
+	  printf ("\t\tbuffer size: %u\n", md.rx_queues[e].buffer_size);
+	  printf ("\t\tthread id: %u\n", thread_data[ti].id);
+	  printf ("\t\tthread connection index: %u\n", thread_data[ti].index);
+	  printf ("\t\tthread running: ");
+	  if (thread_data[ti].isRunning)
+	    printf ("yes\n");
+	  else
+	    printf ("no");
+	}
+      printf ("\ttx queues:\n");
+      for (e = 0; e < md.tx_queues_num; e++)
+	{
+	  printf ("\tqueue id: %u\n", md.tx_queues[e].qid);
+	  printf ("\t\tring size: %u\n", md.tx_queues[e].ring_size);
+	  printf ("\t\tbuffer size: %u\n", md.tx_queues[e].buffer_size);
+	}
+      printf ("\tlink: ");
+      if (md.link_up_down)
+	printf ("up\n");
+      else
+	printf ("down\n");
+    }
+  free (buf);
+}
+
+int
+add_epoll_fd (int epfd, int fd, uint32_t events)
+{
+  if (fd < 0)
+    {
+      DBG ("invalid fd %d", fd);
+      return -1;
+    }
+  struct epoll_event evt;
+  memset (&evt, 0, sizeof (evt));
+  evt.events = events;
+  evt.data.fd = fd;
+  if (epoll_ctl (epfd, EPOLL_CTL_ADD, fd, &evt) < 0)
+    {
+      DBG ("epoll_ctl: %s fd %d", strerror (errno), fd);
+      return -1;
+    }
+  DBG ("fd %d added to epoll", fd);
+  return 0;
+}
+
+int
+mod_epoll_fd (int epfd, int fd, uint32_t events)
+{
+  if (fd < 0)
+    {
+      DBG ("invalid fd %d", fd);
+      return -1;
+    }
+  struct epoll_event evt;
+  memset (&evt, 0, sizeof (evt));
+  evt.events = events;
+  evt.data.fd = fd;
+  if (epoll_ctl (epfd, EPOLL_CTL_MOD, fd, &evt) < 0)
+    {
+      DBG ("epoll_ctl: %s fd %d", strerror (errno), fd);
+      return -1;
+    }
+  DBG ("fd %d moddified on epoll", fd);
+  return 0;
+}
+
+int
+del_epoll_fd (int epfd, int fd)
+{
+  if (fd < 0)
+    {
+      DBG ("invalid fd %d", fd);
+      return -1;
+    }
+  struct epoll_event evt;
+  memset (&evt, 0, sizeof (evt));
+  if (epoll_ctl (epfd, EPOLL_CTL_DEL, fd, &evt) < 0)
+    {
+      DBG ("epoll_ctl: %s fd %d", strerror (errno), fd);
+      return -1;
+    }
+  DBG ("fd %d removed from epoll", fd);
+  return 0;
+}
+
+void *
+memif_rx_poll (void *ptr)
+{
+  memif_thread_data_t *data = (memif_thread_data_t *) ptr;
+  memif_connection_t *c = &memif_connection[data->index];
+  int err;
+  uint16_t rx = 0, tx = 0, fb = 0;
+
+  data->rx_bufs = malloc (sizeof (memif_buffer_t) * MAX_MEMIF_BUFS);
+  data->tx_bufs = malloc (sizeof (memif_buffer_t) * MAX_MEMIF_BUFS);
+  data->rx_buf_num = 0;
+  data->tx_buf_num = 0;
+
+  data->isRunning = 1;
+  INFO ("pthread id %u starts in polling mode", data->id);
+
+  while (1)
+    {
+      if (c->pending_del)
+	goto close;
+
+      /* receive data from shared memory buffers */
+      err =
+	memif_rx_burst (c->conn, data->qid, data->rx_bufs, MAX_MEMIF_BUFS,
+			&rx);
+      if (err != MEMIF_ERR_SUCCESS)
+	{
+	  INFO ("memif_rx_burst: %s", memif_strerror (err));
+	  data->rx_buf_num += rx;
+	  goto error;
+	}
+      data->rx_buf_num += rx;
+      if (rx == 0)
+	{
+	  continue;
+	}
+
+      DBG ("thread id: %u", data->id);
+
+      DBG ("received %d buffers. %u/%u alloc/free buffers",
+	   rx, data->rx_buf_num, MAX_MEMIF_BUFS - data->rx_buf_num);
+
+      err =
+	memif_buffer_alloc (c->conn, data->qid, data->tx_bufs,
+			    data->rx_buf_num, &tx);
+      if (err != MEMIF_ERR_SUCCESS)
+	{
+	  INFO ("memif_buffer_alloc: %s", memif_strerror (err));
+	  data->tx_buf_num += tx;
+	  goto error;
+	}
+      data->tx_buf_num += tx;
+      DBG ("allocated %d/%d buffers, %u free buffers",
+	   tx, data->rx_buf_num, MAX_MEMIF_BUFS - data->tx_buf_num);
+
+      int i;
+      for (i = 0; i < rx; i++)
+	{
+	  resolve_packet ((void *) (data->rx_bufs + i)->data,
+			  (data->rx_bufs + i)->data_len,
+			  (void *) (data->tx_bufs + i)->data,
+			  &(data->tx_bufs + i)->data_len, c->ip_addr);
+	}
+
+      /* mark memif buffers and shared memory buffers as free */
+      err = memif_buffer_free (c->conn, data->qid, data->rx_bufs, rx, &fb);
+      if (err != MEMIF_ERR_SUCCESS)
+	INFO ("memif_buffer_free: %s", memif_strerror (err));
+      data->rx_buf_num -= fb;
+
+      DBG ("freed %d buffers. %u/%u alloc/free buffers",
+	   fb, data->rx_buf_num, MAX_MEMIF_BUFS - data->rx_buf_num);
+
+      err =
+	memif_tx_burst (c->conn, data->qid, data->tx_bufs, data->tx_buf_num,
+			&tx);
+      if (err != MEMIF_ERR_SUCCESS)
+	{
+	  INFO ("memif_tx_burst: %s", memif_strerror (err));
+	  goto error;
+	}
+      DBG ("tx: %d/%u", tx, data->tx_buf_num);
+      data->tx_buf_num -= tx;
+    }
+
+error:
+  INFO ("thread %u error!", data->id);
+  goto close;
+
+close:
+  err = memif_buffer_free (c->conn, data->qid, data->rx_bufs, rx, &fb);
+  if (err != MEMIF_ERR_SUCCESS)
+    INFO ("memif_buffer_free: %s", memif_strerror (err));
+  data->rx_buf_num -= fb;
+  DBG ("freed %d buffers. %u/%u alloc/free buffers",
+       fb, data->rx_buf_num, MAX_MEMIF_BUFS - data->rx_buf_num);
+  free (data->rx_bufs);
+  free (data->tx_bufs);
+  data->isRunning = 0;
+  INFO ("pthread id %u exit", data->id);
+  pthread_exit (NULL);
+}
+
+void *
+memif_rx_interrupt (void *ptr)
+{
+  memif_thread_data_t *data = (memif_thread_data_t *) ptr;
+  memif_connection_t *c = &memif_connection[data->index];
+  int err;
+  uint16_t rx = 0, tx = 0, fb = 0;
+  struct epoll_event evt, *e;
+  int en = 0;
+  uint32_t events = 0;
+  sigset_t sigset;
+
+  signal (SIGUSR1, user_signal_handler);
+
+  data->rx_bufs = malloc (sizeof (memif_buffer_t) * MAX_MEMIF_BUFS);
+  data->tx_bufs = malloc (sizeof (memif_buffer_t) * MAX_MEMIF_BUFS);
+  data->rx_buf_num = 0;
+  data->tx_buf_num = 0;
+
+  data->isRunning = 1;
+  INFO ("pthread id %u starts in interrupt mode", data->id);
+  int thread_epfd = epoll_create (1);
+
+  /* get interrupt queue id */
+  int fd = -1;
+  err = memif_get_queue_efd (c->conn, data->qid, &fd);
+  if (err != MEMIF_ERR_SUCCESS)
+    {
+      INFO ("memif_get_queue_efd: %s", memif_strerror (err));
+      goto error;
+    }
+  add_epoll_fd (thread_epfd, fd, EPOLLIN);
+
+  while (1)
+    {
+      memset (&evt, 0, sizeof (evt));
+      evt.events = EPOLLIN | EPOLLOUT;
+      sigemptyset (&sigset);
+      en = epoll_pwait (thread_epfd, &evt, 1, -1, &sigset);
+      if (en < 0)
+	{
+	  if (errno == EINTR)
+	    goto close;
+	  DBG ("epoll_pwait: %s", strerror (errno));
+	  goto error;
+	}
+      else if (en > 0)
+	{
+	  /* receive data from shared memory buffers */
+	  err =
+	    memif_rx_burst (c->conn, data->qid, data->rx_bufs, MAX_MEMIF_BUFS,
+			    &rx);
+	  if (err != MEMIF_ERR_SUCCESS)
+	    {
+	      INFO ("memif_rx_burst: %s", memif_strerror (err));
+	      data->rx_buf_num += rx;
+	      goto error;
+	    }
+	  data->rx_buf_num += rx;
+	  if (rx == 0)
+	    {
+	      continue;
+	    }
+
+	  DBG ("thread id: %u", data->id);
+
+	  DBG ("received %d buffers. %u/%u alloc/free buffers",
+	       rx, data->rx_buf_num, MAX_MEMIF_BUFS - data->rx_buf_num);
+
+	  err =
+	    memif_buffer_alloc (c->conn, data->qid, data->tx_bufs,
+				data->rx_buf_num, &tx);
+	  if (err != MEMIF_ERR_SUCCESS)
+	    {
+	      INFO ("memif_buffer_alloc: %s", memif_strerror (err));
+	      data->tx_buf_num += tx;
+	      goto error;
+	    }
+	  data->tx_buf_num += tx;
+	  DBG ("allocated %d/%d buffers, %u free buffers",
+	       tx, data->rx_buf_num, MAX_MEMIF_BUFS - data->tx_buf_num);
+
+	  int i;
+	  for (i = 0; i < rx; i++)
+	    {
+	      resolve_packet ((void *) (data->rx_bufs + i)->data,
+			      (data->rx_bufs + i)->data_len,
+			      (void *) (data->tx_bufs + i)->data,
+			      &(data->tx_bufs + i)->data_len, c->ip_addr);
+	    }
+
+	  /* mark memif buffers and shared memory buffers as free */
+	  err =
+	    memif_buffer_free (c->conn, data->qid, data->rx_bufs, rx, &fb);
+	  if (err != MEMIF_ERR_SUCCESS)
+	    INFO ("memif_buffer_free: %s", memif_strerror (err));
+	  data->rx_buf_num -= fb;
+
+	  DBG ("freed %d buffers. %u/%u alloc/free buffers",
+	       fb, data->rx_buf_num, MAX_MEMIF_BUFS - data->rx_buf_num);
+
+	  err =
+	    memif_tx_burst (c->conn, data->qid, data->tx_bufs,
+			    data->tx_buf_num, &tx);
+	  if (err != MEMIF_ERR_SUCCESS)
+	    {
+	      INFO ("memif_tx_burst: %s", memif_strerror (err));
+	      goto error;
+	    }
+	  DBG ("tx: %d/%u", tx, data->tx_buf_num);
+	  data->tx_buf_num -= tx;
+	}
+    }
+
+error:
+  INFO ("thread %u error!", data->id);
+  goto close;
+
+close:
+  err = memif_buffer_free (c->conn, data->qid, data->rx_bufs, rx, &fb);
+  if (err != MEMIF_ERR_SUCCESS)
+    INFO ("memif_buffer_free: %s", memif_strerror (err));
+  data->rx_buf_num -= fb;
+  DBG ("freed %d buffers. %u/%u alloc/free buffers",
+       fb, data->rx_buf_num, MAX_MEMIF_BUFS - data->rx_buf_num);
+  free (data->rx_bufs);
+  free (data->tx_bufs);
+  data->isRunning = 0;
+  INFO ("pthread id %u exit", data->id);
+  pthread_exit (NULL);
+
+}
+
+/* informs user about connected status. private_ctx is used by user to identify connection
+    (multiple connections WIP) */
+int
+on_connect (memif_conn_handle_t conn, void *private_ctx)
+{
+  long index = (*(long *) private_ctx);
+  int err, i, ti;
+  INFO ("memif connected! index %ld", index);
+  memif_connection_t *c = &memif_connection[index];
+  c->pending_del = 0;
+
+  for (i = 0; i < MAX_QUEUES; i++)
+    {
+      err = memif_set_rx_mode (c->conn, MEMIF_RX_MODE_POLLING, i);
+      if (err != MEMIF_ERR_SUCCESS)
+	INFO ("memif_set_rx_mode: %s qid: %u", memif_strerror (err), i);
+      else
+	{
+	  ti = (index * MAX_QUEUES) + i;
+	  if (thread_data[ti].isRunning)
+	    {
+	      INFO ("thread id: %d already running!", ti);
+	      continue;
+	    }
+	  thread_data[ti].index = index;
+	  thread_data[ti].qid = i;
+	  thread_data[ti].id = ti;
+	  if ((i % 2) == 0)
+	    pthread_create (&thread[ti],
+			    NULL, memif_rx_poll, (void *) &thread_data[ti]);
+	  else
+	    pthread_create (&thread[ti],
+			    NULL, memif_rx_interrupt,
+			    (void *) &thread_data[ti]);
+	}
+
+    }
+  return 0;
+}
+
+/* informs user about disconnected status. private_ctx is used by user to identify connection
+    (multiple connections WIP) */
+int
+on_disconnect (memif_conn_handle_t conn, void *private_ctx)
+{
+  void *ptr;
+  long index = (*(long *) private_ctx);
+  memif_connection_t *c = &memif_connection[index];
+  int i, ti;
+  INFO ("memif disconnected!");
+  /* inform thread in polling mode about memif disconenction */
+  c->pending_del = 1;
+  for (i = 0; i < MAX_QUEUES; i++)
+    {
+      ti = (index * MAX_QUEUES) + i;
+      if (!thread_data[ti].isRunning)
+	continue;
+      if ((i % 2) != 0)
+	pthread_kill (thread[ti], SIGUSR1);	/* interrupt thread in interrupt mode */
+      pthread_join (thread[ti], &ptr);
+    }
+  return 0;
+}
+
+/* user needs to watch new fd or stop watching fd that is about to be closed.
+    control fd will be modified during connection establishment to minimize CPU usage */
+int
+control_fd_update (int fd, uint8_t events)
+{
+  /* convert memif event definitions to epoll events */
+  if (events & MEMIF_FD_EVENT_DEL)
+    return del_epoll_fd (main_epfd, fd);
+
+  uint32_t evt = 0;
+  if (events & MEMIF_FD_EVENT_READ)
+    evt |= EPOLLIN;
+  if (events & MEMIF_FD_EVENT_WRITE)
+    evt |= EPOLLOUT;
+
+  if (events & MEMIF_FD_EVENT_MOD)
+    return mod_epoll_fd (main_epfd, fd, evt);
+
+  return add_epoll_fd (main_epfd, fd, evt);
+}
+
+int
+icmpr_memif_create (long index)
+{
+  if (index >= MAX_CONNS)
+    {
+      INFO ("connection array overflow");
+      return 0;
+    }
+  if (index < 0)
+    {
+      INFO ("don't even try...");
+      return 0;
+    }
+  memif_connection_t *c = &memif_connection[index];
+
+  /* setting memif connection arguments */
+  memif_conn_args_t args;
+  int fd = -1;
+  memset (&args, 0, sizeof (args));
+  args.is_master = 0;
+  args.log2_ring_size = 10;
+  args.buffer_size = 2048;
+  args.num_s2m_rings = 2;
+  args.num_m2s_rings = 2;
+  strncpy ((char *) args.interface_name, IF_NAME, strlen (IF_NAME));
+  strncpy ((char *) args.instance_name, APP_NAME, strlen (APP_NAME));
+  args.mode = 0;
+  /* socket filename is not specified, because this app is supposed to
+     connect to VPP over memif. so default socket filename will be used */
+  /* default socketfile = /run/vpp/memif.sock */
+
+  args.interface_id = index;
+  /* last argument for memif_create (void * private_ctx) is used by user
+     to identify connection. this context is returned with callbacks */
+  int err = memif_create (&c->conn,
+			  &args, on_connect, on_disconnect, NULL,
+			  &ctx[index]);
+  if (err != MEMIF_ERR_SUCCESS)
+    {
+      INFO ("memif_create: %s", memif_strerror (err));
+      return 0;
+    }
+
+  c->index = index;
+
+  c->ip_addr[0] = 192;
+  c->ip_addr[1] = 168;
+  c->ip_addr[2] = c->index + 1;
+  c->ip_addr[3] = 2;
+  return 0;
+}
+
+int
+icmpr_memif_delete (long index)
+{
+  if (index >= MAX_CONNS)
+    {
+      INFO ("connection array overflow");
+      return 0;
+    }
+  if (index < 0)
+    {
+      INFO ("don't even try...");
+      return 0;
+    }
+  memif_connection_t *c = &memif_connection[index];
+
+  int err;
+  /* disconenct then delete memif connection */
+  err = memif_delete (&c->conn);
+  if (err != MEMIF_ERR_SUCCESS)
+    INFO ("memif_delete: %s", memif_strerror (err));
+  return 0;
+}
+
+void
+print_help ()
+{
+  printf ("LIBMEMIF EXAMPLE APP: %s", APP_NAME);
+#ifdef ICMP_DBG
+  printf (" (debug)");
+#endif
+  printf ("\n");
+  printf ("==============================\n");
+  printf ("libmemif version: %s", LIBMEMIF_VERSION);
+#ifdef MEMIF_DBG
+  printf (" (debug)");
+#endif
+  printf ("\n");
+  printf ("memif version: %d\n", MEMIF_VERSION);
+  printf ("commands:\n");
+  printf ("\thelp - prints this help\n");
+  printf ("\texit - exit app\n");
+  printf ("\tconn <index> - create memif (slave-mode)\n");
+  printf ("\tdel  <index> - delete memif\n");
+  printf ("\tshow - show connection details\n");
+  printf ("\tip-set <index> <ip-addr> - set interface ip address\n");
+}
+
+int
+icmpr_free ()
+{
+  /* application cleanup */
+  int err;
+  long i;
+  for (i = 0; i < MAX_CONNS; i++)
+    {
+      memif_connection_t *c = &memif_connection[i];
+      if (c->conn)
+	icmpr_memif_delete (i);
+    }
+
+  err = memif_cleanup ();
+  if (err != MEMIF_ERR_SUCCESS)
+    INFO ("memif_delete: %s", memif_strerror (err));
+
+  return 0;
+}
+
+int
+icmpr_set_ip (long index, char *ip)
+{
+  if (index >= MAX_CONNS)
+    {
+      INFO ("connection array overflow");
+      return 0;
+    }
+  if (index < 0)
+    {
+      INFO ("don't even try...");
+      return 0;
+    }
+  memif_connection_t *c = &memif_connection[index];
+  if (c->conn == NULL)
+    {
+      INFO ("no connection at index %ld", index);
+      return 0;
+    }
+
+  char *end;
+  char *ui;
+  uint8_t tmp[4];
+  ui = strtok (ip, ".");
+  if (ui == NULL)
+    goto error;
+  tmp[0] = strtol (ui, &end, 10);
+
+  ui = strtok (NULL, ".");
+  if (ui == NULL)
+    goto error;
+  tmp[1] = strtol (ui, &end, 10);
+
+  ui = strtok (NULL, ".");
+  if (ui == NULL)
+    goto error;
+  tmp[2] = strtol (ui, &end, 10);
+
+  ui = strtok (NULL, ".");
+  if (ui == NULL)
+    goto error;
+  tmp[3] = strtol (ui, &end, 10);
+
+  c->ip_addr[0] = tmp[0];
+  c->ip_addr[1] = tmp[1];
+  c->ip_addr[2] = tmp[2];
+  c->ip_addr[3] = tmp[3];
+
+  INFO ("memif %ld ip address set to %u.%u.%u.%u",
+	index, c->ip_addr[0], c->ip_addr[1], c->ip_addr[2], c->ip_addr[3]);
+
+  return 0;
+
+error:
+  INFO ("invalid ip address");
+  return 0;
+}
+
+
+int
+user_input_handler ()
+{
+  int i;
+  char *in = (char *) malloc (256);
+  char *ui = fgets (in, 256, stdin);
+  char *end;
+  if (in[0] == '\n')
+    goto done;
+  ui = strtok (in, " ");
+  if (strncmp (ui, "exit", 4) == 0)
+    {
+      free (in);
+      icmpr_free ();
+      exit (EXIT_SUCCESS);
+    }
+  else if (strncmp (ui, "help", 4) == 0)
+    {
+      print_help ();
+      goto done;
+    }
+  else if (strncmp (ui, "conn", 4) == 0)
+    {
+      ui = strtok (NULL, " ");
+      if (ui != NULL)
+	icmpr_memif_create (strtol (ui, &end, 10));
+      else
+	INFO ("expected id");
+      goto done;
+    }
+  else if (strncmp (ui, "del", 3) == 0)
+    {
+      ui = strtok (NULL, " ");
+      if (ui != NULL)
+	icmpr_memif_delete (strtol (ui, &end, 10));
+      else
+	INFO ("expected id");
+      goto done;
+    }
+  else if (strncmp (ui, "show", 4) == 0)
+    {
+      print_memif_details ();
+      goto done;
+    }
+  else if (strncmp (ui, "ip-set", 6) == 0)
+    {
+      ui = strtok (NULL, " ");
+      if (ui != NULL)
+	icmpr_set_ip (strtol (ui, &end, 10), strtok (NULL, " "));
+      else
+	INFO ("expected id");
+      goto done;
+    }
+  else
+    {
+      DBG ("unknown command: %s", ui);
+      goto done;
+    }
+
+  return 0;
+done:
+  free (in);
+  return 0;
+}
+
+int
+poll_event (int timeout)
+{
+  struct epoll_event evt, *e;
+  int app_err = 0, memif_err = 0, en = 0;
+  int tmp, nfd;
+  uint32_t events = 0;
+  memset (&evt, 0, sizeof (evt));
+  evt.events = EPOLLIN | EPOLLOUT;
+  sigset_t sigset;
+  sigemptyset (&sigset);
+  en = epoll_pwait (main_epfd, &evt, 1, timeout, &sigset);
+  if (en < 0)
+    {
+      DBG ("epoll_pwait: %s", strerror (errno));
+      return -1;
+    }
+  if (en > 0)
+    {
+      /* this app does not use any other file descriptors than stds and memif control fds */
+      if (evt.data.fd > 2)
+	{
+	  /* event of memif control fd */
+	  /* convert epolle events to memif events */
+	  if (evt.events & EPOLLIN)
+	    events |= MEMIF_FD_EVENT_READ;
+	  if (evt.events & EPOLLOUT)
+	    events |= MEMIF_FD_EVENT_WRITE;
+	  if (evt.events & EPOLLERR)
+	    events |= MEMIF_FD_EVENT_ERROR;
+	  memif_err = memif_control_fd_handler (evt.data.fd, events);
+	  if (memif_err != MEMIF_ERR_SUCCESS)
+	    INFO ("memif_control_fd_handler: %s", memif_strerror (memif_err));
+	}
+      else if (evt.data.fd == 0)
+	{
+	  app_err = user_input_handler ();
+	}
+      else
+	{
+	  DBG ("unexpected event at memif_epfd. fd %d", evt.data.fd);
+	}
+    }
+
+  if ((app_err < 0) || (memif_err < 0))
+    {
+      if (app_err < 0)
+	DBG ("user input handler error");
+      if (memif_err < 0)
+	DBG ("memif control fd handler error");
+      return -1;
+    }
+
+  return 0;
+}
+
+int
+main ()
+{
+  main_epfd = epoll_create (1);
+  add_epoll_fd (main_epfd, 0, EPOLLIN);
+
+  /* initialize memory interface */
+  int err, i;
+  /* if valid callback is passed as argument, fd event polling will be done by user
+     all file descriptors and events will be passed to user in this callback */
+  /* if callback is set to NULL libmemif will handle fd event polling */
+  err = memif_init (control_fd_update, APP_NAME);
+  if (err != MEMIF_ERR_SUCCESS)
+    INFO ("memif_init: %s", memif_strerror (err));
+
+  for (i = 0; i < MAX_CONNS; i++)
+    {
+      memif_connection[i].conn = NULL;
+      ctx[i] = i;
+    }
+
+  memset (&thread_data, 0, sizeof (memif_thread_data_t) * MAX_THREADS);
+
+  print_help ();
+
+  /* main loop */
+  while (1)
+    {
+      if (poll_event (-1) < 0)
+	{
+	  DBG ("poll_event error!");
+	}
+    }
+}